Vulcanization of rubber and the product thereof



Patented Dec. 20, 1927.

UNITED STATES PATENT-OFFICE.

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GERMANY.

VULCANIZATI ION OI RUBBER AND THE PRODUCT THEREOF.

No Drawing. Applicationfiled April 12, 1927, Serial No. 183,229, and in Germany May 21, 1926.

- The present invention relates to a new and improved process of ,vulcanizing natural or artificial rubber in which a small amount of .the amide of formic acid is employed as a vulcanization accelerator with or without a substance capable of activating the amide of formic acid, such as, for example zinc oxide. Zinc oxide has been found to be very effective for activating the amide of formic acid.

The amide of formic acid possesses the advantage that it is completely non-poisonous and that it is free from caustic or other irritating action. The products of the vulcanization obtained with the aid of this compound have an excellent elasticity.

The vulcanizing process may be carriedout'by any of the methods now well-known in the art. The followin examples serve to illustrate the invention. owever, it is to be understood that-these examples are merely illustrative and that the invention is not limited to the use of the particular materials,

proportions or method specified. 100 parts by weight of raw rubber (smoked sheets), 10 parts by weight of zinc white, 5 parts by weight of sulphur and 1.5 (parts by weight of formamide are subjecte to the vulcanization process for 50 minutes at 140 C. A vulcanized product is obtained, which possesses a high degree of elasticity.

rubber with which a small amount of the amide of formic acid and zinc oxide have been incorporated, 4.)

3. As a new article of manufacture, a vulcanized rubber combined before vulcanization with a small amount of the amide of formic acid.

4., As a new article of manufacture, a vulcanized rubber combined before vulcanization with a small amount of the amide of formic acid and zinc oxide.

In testimony whereof we have hereunto set our hands. l

HEINRICH GI'lNZLER. WALDEMAR ZIESER. 

